The present invention relates to a memory device or unit for lighting control purposes. It is more particularly applicable to the control of the lighting of public telephone kiosks, which are connected to the public lighting network, the latter being switched on at dusk and switched off at dawn. The control of the switching on and off of the lighting system can be carried out by means of a day/night clock or by a photoelectric cell which is sensitive to natural lighting, as a function of the locations. The present invention also applies to the control of the lighting of floor standard lamps, shop windows and signalling, or security lighting sources.
It is known that one of the problems occurring when operating lighting means is to ensure that they function normally, i.e. that their supply voltages are present and that their lighting sources (lamps, tubes, etc) are in a satisfactory state. One possible solution for solving this problem is to send out somebody to see whether the lighting systems are functioning properly, generally at night, or to intercept and collect light presence information and transmit it to a central monitoring station. However, both methods are disadvantageous when there are numerous lighting means to be monitored and when the latter are distributed over a vast territory, e.g. in the case of public telephone kiosks.